Distribution of gallium nanocrystals in Ga/MCM-41 mesocomposites by continuous-flow hyperpolarized 129Xe NMR
Weiping Zhang1, Christopher I Ratcliffe, Igor L Moudrakovski
1Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada. wpzhang@dicp.ac.cn
Abstract:
The distribution of gallium nanocrystals in mesoporous MCM-41 host were analyzed by continuous-flow hyperpolarized 129Xe NMR spectroscopy. In contrast to unclear TEM images for the high metal contents, laser-polarized 129Xe probe can detect the whole distribution of gallium in the MCM-41 host. It is found that gallium nanocrystals are included in the mesochannels of MCM-41; a part of them also remains in the interparticle voids. The distribution of gallium metal in MCM-41 is heterogeneous. Not all the mesochannels host metallic gallium even at a high gallium loading of 65.1 wt %. Variable temperature measurements can provide information on the xenon adsorption parameters. This approach opens a sensitive way to probe the distribution of high content species in porous host materials.
